In: Statistics and Probability
A researcher believes that college students today have different
IQ scores than in previous years. To investigate this belief, he
randomly samples 41 currently enrolled students and records their
IQ scores. The scores have a mean of 111 and a standard deviation
of 12.4. A local census taken 10 years ago shows that the mean IQ
of students enrolled during that time was 115.
The degrees of freedom for this sample is
[ Select ]
["41", "40", "39", "38", "-2.201",
"-2.407", "2.704", "2.021", "-2.07", "+2.07", "-0.32", "+0.32",
"reject the null hypothesis", "fail to reject the null hypothesis",
"IQ is probably different", "IQ is not different"]
Using a two tailed alpha level of .01, the appropriate critical
value is
[ Select ]
["41",
"40", "39", "38", "-2.201", "-2.407", "2.704", "2.021", "-2.07",
"+2.07", "-0.32", "+0.32", "reject the null hypothesis", "fail to
reject the null hypothesis", "IQ is probably different", "IQ is not
different"]
The obtained value of the appropriate statistic
is
[
Select ]
["41", "40", "39", "38",
"-2.201", "-2.407", "2.704", "2.021", "-2.07", "+2.07", "-0.32",
"+0.32", "reject the null hypothesis", "fail to reject the null
hypothesis", "IQ is probably different", "IQ is not different"]
What is your decision?
[ Select ]
["41", "40", "39", "38", "-2.201", "-2.407", "2.704",
"2.021", "-2.07", "+2.07", "-0.32", "+0.32", "reject the null
hypothesis", "fail to reject the null hypothesis", "IQ is probably
different", "IQ is not different"]
Is the IQ of currently enrolled college students different than in
previous years?
[ Select ]
["41",
"40", "39", "38", "-2.201", "-2.407", "2.704", "2.021", "-2.07",
"+2.07", "-0.32", "+0.32", "reject the null hypothesis", "fail to
reject the null hypothesis", "IQ is probably different", "IQ is not
different"]